Small hot water vacuum extraction machines have come into recent vogue and are employable by the housewife for rug cleaning. Large hot water vacuum extraction machines have been commercially employed for many years under the general term "steam cleaners". The steam cleaners employ a source of very hot water which is sprayed by means of a nozzle mounted to the rear of a vacuum extraction head borne at the lower end of a tubular wand carried by the operator. The tubular wand is hose connected to a dirty water accumulation tank within the steam cleaner chassis. A narrow slot within the vacuum head is subject to vacuum pressure, through the wand and hose, such that, the dirty water adjacent the area of impact of the hot water jetted from the nozzle onto the underlying rug to be cleaned, is sucked up and returned to the machine or to a corresponding dumping mechanism. Such commercial machines are complex and, in many cases, the source of hot water and the sump tank were carried by a motor vehicle such as a truck, requiring long hose connections leading to the interior of the home being cleaned.
A number of patents have issued in recent years to Parise and Sons, Inc., the common corporate assignee of the present application, directed small hot water vacuum machines capable of operation by a housewife and directed to that market. Representative patents are:
______________________________________ 3,896,521 HOME CLEANING SYSTEM 3,911,524 STEAM CLEANER DUMP BUCKET 4,009,728 WATER VALVE ASSEMBLY 4,015,589 STEAM CLEANER PROTECTION SCREEN 4,046,989 HOT WATER EXTRACTION UNIT HAVING ELECTRICAL IMMERSION HEATER 4,075,733 CLEANING HEAD 4,078,908 DUMP BUCKET FOR A WET-DRY VACUUM SYSTEM HAVING IMPROVED LIQUID FLOW CHARACTERISTICS 4,083,705 DUMP BUCKET FOR A WET/DRY VACUUM SYSTEM 4,088,462 HOT-WATER EXTRACTION UNIT 4,122,579 STEAM CLEANER DUMP BUCKET ______________________________________
Most of the hot water vacuum extraction machines developed by Parise and Sons, Inc. are characterized by a plastic casing or housing of modified parallelepiped form, which bears separately a hot water supply tank and a removable dump tank. The dump tank receives the accumulated dirty water returned from the surface being cleaned by vacuum application through the dump tank, connecting hose, and wand to vacuum pick-up head.
Several major mechanical elements are carried internally of the casing to assist in these functions including an electric motor driven pump for pumping the hot water from the hot water supply tank to the spray nozzle borne by the vacuum head. Further, in order to create the vacuum pressure within the dump tank and also transmit it from the dump tank to the vacuum pick up head through the hose and wand leading thereto, an electric motor driven vacuum pump is also mounted within the casing. It underlies the removable dump tank in certain models. That component is formed of two major elements, the vacuum pump or blower and the electrical drive motor, coaxially mounted thereto. A suction fan or blower is shaft mounted within a vacuum pump casing and normally within a portion of a casing which takes a scroll form and which terminates in a tubular exhaust pipe leading tangentially away from the pump casing. The shaft bearing suction fan or blower is normally integral with the electrical motor rotor. The motor stator concentrically surrounds the rotor and is fixed to the motor casing, with that casing integrated to the vacuum pump casing itself. An air inlet to the vacuum pump is provided within the horizontal upper wall of the pump casing which underlies the lower end of the cylindrical dump tank and which communicates with a cylindrical riser tube within the dump tank lower section. The bottom of riser tube is sealed in communication, through the top horizontal wall of the vacuum pump casing with the plenum chamber. An inverted cup-shaped cover seals to the upwardly open top of the dump tank. A tubular coupling or connector projects radially outwardly from the side of the cover to make connection to a flexible hose which, in turn, leads to the vacuum wand and the vacuum head carried by that wand. Rotation of the suction fan or blower for the vacuum pump by the electrical drive motor creates a vacuum pressure within the dump tank, which vacuum is transmitted by the hose and wand to the vacuum head. Positive pressure air exhausts through the scroll portion of the vacuum pump casing and exits through the tubular end of the scroll. Normally, an elbow connected to the scroll tubular outlet is fixedly mounted to the interior of the extraction machine casing opens to the exterior of the casing through a hole within the bottom wall of the lower casing section.
In such prior art construction, there is a necessity to cool the electrical drive motor by permitting cooling air to be drawn into the motor casing interior by a second shaft mounted fan within the electric motor itself and at the end of the motor rotor remote from the vacuum pump blower section. The pitch of the cooling fan, its speed of rotation and the location of inlet and outlet holes within the electric motor casing insure forced passage of cooling air over the motor stator and rotor during vacuum pump operation. Slots are normally provided within the hot water vacuum extraction machines lower casing section at one point within the casing sidewall or bottom wall to allow cooling air to reach the motor while the heated air is permitted to exit from the interior of the casing after discharge from the electric motor casing itself via another set of casing sidewall or bottom wall slots. In order to accomplish this, shrouds, baffle plates or the like may be provided for directing a confined cooling air stream to and/or from the motor.
As may be appreciated, with the relatively high velocity positive air flow exiting from the scroll at the outlet side of the vacuum pump directly to the exterior of the machine casing, and with the cooling air flow from the electric drive motor also exiting directly to the machine exterior through openings within the sidewall or bottom wall of the machine casing, a relatively high noise level exists during operation of the machine. This is both due to the velocity of the air and the normal noise associated with the operation of electrical water pump drive motor and the vacuum pump drive motor, particularly the vacuum pump drive motor. Further, due to the confined nature of the cooling air flow and that of the exhaust air from the vacuum pump, such noise is attenuated.
It is, therefore, a primary object of the present invention to provide an improved hot water vacuum extraction machine in which the noise level of the cleaner is relatively low, and wherein the exhaust air from the vacuum pump and the cooling air passing through the vacuum pump drive motor is expanded prior to leaving the extraction machine casing, without loss of machine component performance.